Evaluation of commercial landscaping mulch for possible contamination from CCA
Evaluation of commercial landscaping mulch for possible contamination from CCA
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DOI：
10.1016/j.wasman.2006.09.013
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发表时间：
2007-01-01
期刊：
影响因子：
8.1
通讯作者：
Shibata, Tomoyuki
中科院分区：
文献类型：
--
作者：
Jacobi, Gary;Solo-Gabriele, Helena;Shibata, Tomoyuki
用铬酸铜砷酸盐（CCA）处理的木材在建筑和拆除（C&D）碎片中发现，从C&D碎片中回收的木材的常见用途是生产覆盖物。鉴于CCA处理过的木材中的金属浓度很高，一小部分CCA处理过的木材可以使覆盖物中的金属浓度超过监管阈值。本研究的目的是确定消费者美化覆盖物中CCA处理过的木材的污染程度，并确定是否可以使用视觉方法或快速X射线荧光（XRF）技术来识别可疑的覆盖物。在整个佛罗里达州（美国）采集样品，并进行目视和化学评价。视觉分析的重点是记录木片的尺寸分布，样品是否是人工着色的，以及它们是否含有胶合板碎片，这表明样品部分是由回收的C&D木材制成的。化学分析包括测量总可回收金属、根据标准化合成沉淀浸出程序（SPLP）的可浸出金属和XRF分析。视觉识别方法，如着色剂添加或存在的胶合板，被认为是有效的初步筛选可疑的覆盖。XRF分析被认为是有效的识别覆盖物含有高于75毫克/公斤的砷。对于未着色且不含C&D木材证据的覆盖物样品，没有超过50微克/升的可沥滤金属浓度，只有3%的可回收金属超过10毫克/千克。大部分的彩色覆盖物由回收的C&D木材含有1%至5%的CCA处理的木材（15%的最大分数），导致可浸出的金属超过50微克/升，总的可回收金属超过10毫克/公斤。在评价的覆盖物样品中测得的最大砷浓度为230 mg/kg，高于佛罗里达居民直接暴露监管指南2.1 mg/kg。(C)2006爱思唯尔有限公司版权所有。
Wood treated with chromated copper arsenate (CCA) is found in construction and demolition (C&D) debris, and a common use for wood recycled from C&D debris is the production of mulch. Given the high metals concentrations in CCA-treated wood, a small fraction of CCA-treated wood can increase the metal concentrations in the mulch above regulatory thresholds. The objective of this study was to determine the extent of contamination of CCA-treated wood in consumer landscaping mulch and to determine whether visual methods or rapid X-ray fluorescence (XRF) technology can be used to identify suspect mulch. Samples were collected throughout the State of Florida (USA) and evaluated both visually and chemically. Visual analysis focused on documenting wood-chip size distribution, whether the samples were artificially colored, and whether they contained plywood chips which is an indication that the sample was, in part, made from recycled C&D wood. Chemical analysis included measurements of total recoverable metals, leachable metals as per the standardized synthetic precipitation leaching procedure (SPLP), and XRF analysis. Visual identification methods, such as colorant addition or presence of plywood, were found effective to preliminarily screen suspect mulch. XRF analysis was found to be effective for identifying mulch containing higher than 75 mg/kg arsenic. For mulch samples that were not colored and did not contain evidence of C&D wood, none exceeded leachable metal concentrations of 50 mu g/L and only 3% exceeded 10 mg/kg for recoverable metals. The majority of the colored mulch made from recycled C&D wood contained from 1% to 5% CCA-treated wood (15% maximum fraction) resulting in teachable metals in excess of 50 mu g/L and total recoverable metals in excess of 10 mg/kg. The maximum arsenic concentration measured in the mulch samples evaluated was 230 mg/kg, which was above the Florida residential direct exposure regulatory guideline of 2.1 mg/kg. (C) 2006 Elsevier Ltd. All rights reserved.